Isolation rearing has been shown to cause dramatic changes in variables ranging from behavior to neurotransmittors to brain morphology. The deleterious consequences of social isolation has been demonstrated in both mammalian as well as non-mammalian species. Eleven three year old sooty mangabeys were subjects in an SIV-related protocol since birth. Nine were isolated while 2 were housed with their mother only for the first 2 years. These 11 three year old mangabeys served as test subjects while four, three year olds raised by their mother in a social group served as controls. The purpose of this study was to expose the test subjects to a step by step socialization process and to investigate associated behavioral and physiological changes in relation to controls. Preliminary data show that stereotopies exhibited by individuals prior to the study when housed individually decrease over time after pairing with a partner and after individuals are moved into larger groupings. Subjects did exhibit a stress response as evidenced by increases in cortisol and decreases in CD4+CD8- helper cells 24 hours following the pairing with a partner and grouping with other individuals as compared to controls, although these changes returned to baseline levels within a week. Individuals who played more showed a faster recovery to baseline in CD4+CD8- helper cells following the grouping. Preliminary data shows that while previously isolated sooty mangabeys exhibit a stress response following increases in socialization (partner or grouping), given a slow progression and habituation period, most do adapt to the new social circumstances and develop species typical social behaviors while reducing isolation-induced stereotopies.